HVAC systems can be used to regulate the environment within an enclosure. Typically, an air blower is used to pull air from the enclosure into the HVAC system through ducts and push the air back into the enclosure through additional ducts after conditioning the air (e.g., heating or cooling the air). Understanding the airflow through a HVAC system in the design stage is helpful to prevent cooling or heating variances in the enclosure. There is also a need to understand the actual airflow from HVAC equipment into the enclosure after installation.
For installed HVAC systems, the actual airflow rate is often needed. For example, regulations and the Leadership in Energy and Environmental Standards (LEED) initiative require the measurement of airflow during installation and operation. During construction, a commissioning phase is typically conducted to inspect a new air conditioning installation, and verify that the new system is running properly and efficiently. The commissioning phase can be expensive, labor intensive and time prohibitive. Additionally, the measurements obtained during commissioning may be less than exact and require adjustments after construction. Monitoring the actual airflow of a HVAC system after installation can also be difficult due to the expense and unreliability of sensors and other equipment needed.